Messages in this thread | | | Date | Mon, 16 Jul 2012 01:21:20 -0700 | From | Anton Vorontsov <> | Subject | Re: [PATCH] power_supply: Added support for power supply attribute sources |
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Hi Ramakrishna,
On Mon, Jun 25, 2012 at 06:07:22PM +0530, Ramakrishna Pallala wrote: > On some platforms one driver(or HW chip) may not be able to provide all > the necessary attributes of the power supply connected to the platform or > may provide very limited info which can be used by core/primary drivers. > > For example a temperature sensor chip placed near the battery can be used > to report battery ambient temperature but it does not makes sense to register > sensor driver with power supply class. Or even a ADC driver or platform > driver may report power supply properties like voltage/current or charging > status but registering all those driver with power supply class is not a > practical or ideal approach. > > This patch adds the generic support to register the drivers as power > supply attribute(properties) sources and adds an interface to read > these attributes from power supply class drivers.
So, you would add power_supply_attributes_register() calls into ADC drivers? This is not right.
The right approach would be to write a power supply driver that would accept ADC device/channel (or just a callback) for getting needed information to report.
I.e.
/* * Here I just made up adc_channel struct for simplicity of the * example; For real ADC dev, you really want to use Industrial IO * framework, i.e. include/linux/iio/iio.h. */ struct adc_channel { ... int (*get_value)(struct *adc_channel); };
struct adc_power_supply_platform_data { struct adc_channel *voltage; struct adc_channel *current; };
And the "adc power supply" driver would then call:
... case POWER_SUPPLY_PROP_CURRENT: prop->intval = voltage->get_value(voltage); ...
Sure, sometimes it's not only ADC, but sensors, regulators and so forth. So pass all the devices to the power_supply driver, and teach the driver to work with the facilities.
As an example of such a platform driver, see drivers/power/pda_power.c. It is a generic driver for platforms with two power sources (AC/USB), optinally connected to a battery.
[..] > +struct power_supply_attr_query { > + enum power_supply_property property; > + enum power_supply_type type; > + /* variable to store result */ > + union power_supply_propval res; > +}; [...] > +extern int power_supply_get_external_attr( > + struct power_supply_attr_query *query);
And even if we'd consider adding this feature, the interface seems very limited. What if there are two, say, batteries?
I don't think it's the right approach, sorry.
Kind regards,
-- Anton Vorontsov Email: cbouatmailru@gmail.com
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